This invention relates generally to multiple fluid pumps, and in particular to multiple fluid pumps requiring an accurate ratioing of fluids being pumped.
A number of pumping systems of the prior art used devices to detect the end of stroke of the piston.
These devices for detecting the end of the piston stroke included toggle switches, induction switches and proximity switches of various types. The primary purpose of these devices was to count the number of piston strokes and thus measure the volume of fluid pumped knowing the piston diameter and length of stroke.
All of the prior art systems were designed to pump a single fluid or slurry.
They were not interested in accurate ratioing of two or more fluids.
Those devices that were interested in ratioing of two or more fluids utilized, variously, pumps which were mechanically geared together to cause them to pump at different rates.
When pumping fluids of different viscosities, these mechanically configured pumping systems could not accurately ratio the fluids at all pumping speeds without taking into consideration special design features relative to the differences in viscosity of each fluid.
For these prior art multiple fluid pumping systems, it was extremely difficult to change the pumping ratio.